Interconnected multipole circuit breaker



C. A. BODGE INTERC ONNECTED MULTIPOLE CIRCUIT BREAKER Feb.4, 1969 Sheeti of 5 Filed Dec. 20,

Feb. 4, 1969 c. A. BODGE 3,426,301

INTERCONNECTEI) MULTIPOLE CIRCUIT BREAKER Filed Dec. 20, 1966 Sheet g ofs c. A. some;

Feb. 4, 1969 INTERCONNECTED MULTIPOLE CIRCUIT BREAKER Sheet Filed Dec.20, 1966 United States Patent 3 Claims ABSTRACT OF THE DISCLOSURE Amechanism for interconnecting the poles of a multipole circuit breakerto disengage the contacts in all of the poles upon disengagement of thecontacts in any one of the poles and particularly for circuit breakersof the type wherein each pole is provided with fixed and movablecontacts operated by an interconnecting toggle linkage. Each togglelinkage is provided with a latch for tripping it to disengage thecontacts in one pole in response to an electromagnetic overload sensingdevice. A rotary shaft, interconnecting the poles, is provided withmeans, one for each pole, for tripping all of the toggle linkages in allpoles when one is tripped upon overload so as to disengage all of thecontacts of the breaker.

Background 0 the invention The invention belongs in the multipolecircuit breaker art in which disengagement of the contacts in all of thepoles occurs upon disengagement of the contacts in any one of the poles.

In the past, various attempts have been made to interconnect the polesin a multipole circuit breaker for interrupting the flow of currentthrough all of the poles upon the occurrence of an overload condition inany one of the poles. The most common mechanism for accomplishing thisis provided with a shaft extending between the poles with a plurality oflobes projecting therefrom, a lobe in each pole being located so as tocoordinate with the motion of the contact arm and the armature in apole. An overload in any one of the poles causes the contact arm toengage the lobe associated therewith and rotate the shaft and theremaining lobes into engagement with the armatures in each of the poles,the armatures then operating latches to disengage all the contacts. Thistype of mechanism requires the contact arm, shaft assembly, andarmatures of all of the poles to be held to very close tolerances toensure pole-to-pole operation of the latches. Any small shifting of theparts will cause a malfunction since the armatures are relativelyinsensitive and must be rotated by the lobes through a considerabledistance before the armatures actuate the latches. The distance is not aproblem when the armature is actuated by the overload sensing means butbecomes critical when actuated 'by the lobe. For example, in a presentcommercial design, each pole must be calibrated to trip within tolerancebetween .010 and .020 inch before the armature reaches the limit of itstravel to ensure tripping of the latches by the lobe actuated armature.This requires that each of the poles be adjusted to and cannot shiftmore than .010 inch relative to each other. In a circuit breakeremploying, for example, six poles, this tolerance limitation becomesvery critical, thereby materially increasing the cost and decreasing thereliability of such devices. In addition, all of the prior artmechanisms utilize the motion of the end of the contact arm to operatethe armatures of adjacent poles. Since the force available at the end ofthe contact arm is relatively low in the contacts-open position, theadditional problem of inadequate force available for unlatching adjacentpoles is presented by this type of circuit breaker.

Summary of the invention Accordingly the present invention overcomesthese difficulties by providing an interconnecting mechanism whichoperates directly on the latches without first operating the armatures.This reduces the distance that the interconnecting mechanism must travelbefore tripping the contacts. Since the latch is very sensitive, asopposed to the armature as set forth above, this interconnectingmechanism ensures tripping of all the contacts.

An interconnected multipole circuit breaker constructed in accordancewith the present invention is composed of a plurality of poles, eachpole being comprise-d of a pair of contacts, one of which is carried bya :movable arm for movement into and out of engagement with the other ofthe contacts. Means including a toggle linkage assembly is connected tothe movable arm for normally maintaining engagement of the contacts anda latch is provided for collapsing or tripping the toggle assembly tocause disengagement of the contacts. Overload sensing means is providedfor operating one latch in one pole in response to a predeterminedcondition, and interconnecting means is provided for disengaging thecontacts in all of the poles upon disengagement of the contacts in saidone pole. The interconnecting means comprises means interconnecting allof the poles and operated by the movable arm in the pole wherein thecontacts first disengage for operating the latches in each of theremaining poles to disengage the contacts therein.

Brief description 0 f the drawings FIG. 1 is a side elevation of thecircuit breaker of the present invention with portions .of the housingfragmented and showing the circuit breaker contacts in the on orcontacts-closed position;

FIG. 2 is a left-handed end elevation of FIG. 1, partly in section,showing a two pole circuit breaker constructed in accordance with thepresent invention;

FIG. 3 is an enlarged side elevation similar to FIG. 1 with portions ofthe device omitted for clarity of illustration and showing the circuitbreaker contacts in the off or contacts-open position;

FIG. 4 is an enlarged fragmentary elevation of a por tion of theinvention showing the contacts in the on or contacts-closed position;and

FIG. 5 is an enlarged fragmentary elevation similar to FIG. 4 butshowing the contacts in an otf or contactsopen position.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Description of the preferred embodiment Referring particularly to FIGS.1 to 3, a preferred structural embodiment of one pole of a multipolecircuit breaker 1 is illustrated. In the interest of simplicity ofdescription, some of the details of the circuit breaker not necessary toa full understanding of the invention will be omitted. However, acomplete description of the construction and operation of the circuitbreaker mechanism per se may be obtained by reference to US. Patent3,388,357 based on application 577,086 which is a continuation of theapplication of Clifford A. Bodge and Martin W. Lawson, Ser. No. 298,536,filed July 26, 1963, and now abandoned, and assigned to the sameassignee as the present application 603,360. The circuit breaker 1 iscomprised of a housing 3 having a pair of side portion 5 and a bottomportion 7, the housing being formed of a suitable electricallyinsulative material such as, for example, a moldable, phenolic resin.The housing 3 constitutes supporting means for the circuit breakermechanism. Housing 3 contains suitable openings 9, 11 for receivingconductive terminals 13 and 15, respectively. Terminal 13 carries anelectrically conductive contact plate 17 carrying a fixed contact 19'.The housing 3 further includes upper and lower end portions 21 and 23extending the width of the housing 3, the lower end portion 23 includingapertures 25 receiving fasteners 27 for retaining the housing sideportions in tight-fitting engagement. Mounted on the top of housing 3 isa cover member 29 having tab portions 31 bracketing the housing 3 andapertured at 33 for receiving a pair of fasteners 35.

The circuit breaker 1 includes a toggle lever assembly, generallyindicated by reference character 37, which is comprised of a toggleoperating lever 39, formed of insulating material, received within anopening 41 formed within the upper end portion 21 of the housing 3. Thecover 29 includes an opening 43 through which toggle lever 39 projects,the opening 43 being of a size sufficient to allow for movement of thetoggle lever 39 between the on position illustrated in FIG. 1 and theoff position illustrated in FIG. 3. Cover opening 43 is alsosufficiently large to allow viewing of the lever surfaces 45, 47, whichmay be printed with the wording off and on, respectively.

Toggle lever 39 is provided with an extension 53 and is pivotallymounted on a pin 49 supported on a toggle frame 51. A toggle spring 55,one end of which abuts a portion of the frame 51 and the other end ofwhich abuts a portion of extension 53, urges the toggle assembly 37toward the off position illustrated in FIG. 3. The toggle frame 51extends downwardly through the housing 3 and forms a support 63 forsupporting an overload or current sensing assembly 65, the latter beingcomprised of an electromagnet 67 having a coil 69 and a core 71. One endof the coil 69 is electrically connected through a conductor 73 to theterminal 15 and the other end of the coil is connected to a flexibleconductor 75 by a connector 77. An armature 79 is pivotally mounted on ashaft 81 secured to the toggle frame 51 for pivotal movement towards andaway from the electromagnet core 71. Armature 79 is urged to rotate in acounterclockwise direction, as viewed in FIG. 1, into engagement with atab 83 formed on frame 51 by a spring 85 coiled about an adjustable pin87. The tab portion 83 acts as a calibrated stop for armature 79 and maybe bent or calibrated to control the amount of electromagnetic forcenecessary to cause the armature 79 to pivot about shaft 81 and engagethe armature core 71. Armature 79 includes a core engaging portion 89extending in a first direction and a pair of legs 91, 93 extending in asecond direction. The end of leg 91 is provided with a camming surface95, the purpose of which will be hereinafter set forth, while leg servesas a balancing extension to counterbalance the armature 79 and 91.

Mounted on the lower portion of frame 51 is a conductive switch arm orcontact arm 97 having a moveable contact 99 secured thereto for movementinto and out of engagement with the fixed contact 19. The contact arm 97is electrically connected through connector 101 to the end of conductor75. Thus a completed electrical circuit may be provided through terminal15, coil 69 of electromagnet 67, conductor 75, contact arm 97, movablecontact 99, fixed contact 19, and terminal 13.

Contact arm 97 is provided with an elongate slot 103 having a pin 105extending thererthrough and engaging a pair of legs 106 formed on theframe 51. The contact arm 97 is urged by spring 107 towards rotation ina clockwise direction, as viewed in FIG. 1, from the contactsclosedposition to the contracts-open position. One end of spring 107 bearsagainst leg 106 of frame 51 and the other end bears against the contactarm 97. The contact arm 97 is connected to the toggle lever 39 by acollapsible toggle linkage assembly 109. The assembly 109 includes alower link 111 pivotally connected to contact arm 97 by a pivot pin 113,and to a center link 115 by a pivot or hinge pin 117. The other end ofthe center link 115 is connected to the extension 53 by a pivot pin 119tocomplete the toggle linkage assembly 109.

As best illustrated in FIG. 1, the pivot point at pivot pin 117 may takea position to the left of a line passing through the centers of pins 113and 119. A tab portion 121 formed on lower link 111 bears against thecenter link 115 in the tripped position of parts shown in FIG; 3. Ifforces are applied at the ends of the linkage assembly 109, that is, atpins 113 and 119, the linkage assembly will tend to collapseto the leftas shown in'FIG. -3. This is prevented, however, by a rotary latchreleasing mechanism 123 which provides a stop against pivotal movementof the center link 115 about pin 117. Rotary latch 123 is mounted on aslotted shaft 125 which rotates with-the latch 123, the shaft 125 havinga solid-right-hand half 127 normally engaging a lip 129 formed in the.lower portion of center link 115 to pervent rotation of link 115 aboutpin 117 and collapse of the assembly 109. However, upon clockwiserotation of the rotary latch 123 and the shaft 125, the solid half 127of the shaft 125 is rotated out of engagement with the lip 129, therebyreleasing the center link 115 and permitting the same to rotate aboutthe shaft 117 to effect collapse or'tripping of the toggle linkageassembly 109. A spring 131 is coiled about the shaft 125 for biasing therotary latch 123 against a stop 120 on link 111 in a counterclockwisedirection as viewed in the FIG. 1.

In operation, the circuit breaker 1 is connected to the circuit orcomponent to be protected at terminals Band 15. Previously the devicehas been calibrated by bending tab 83 and tensioning spring to fix theamount of the electromagnetic force required to actuate armature 79, andhence to determine the amount of overload required to trip the circuitbreaker and interrupt the flow of current therethrough. The toggle lever39 is then switched to the on or contact-closed position illustrated inFIG. 1 wherein the links 111 and 115 of linkage assembly 109 act rigidlyto swing arm 97 counterclockwise so as to move contact 99 intoengagement with stationary contact 19.

When an overload condition occurs in the circuit through electromagnet67, the armature 79 is actuated and pivoted about shaft 81 to move thecamming surface into engagement with lug 122 on the rotary latch 123 androtate the latch 123 and slotted shaft 125. In this movement the surface95 passes by stop 120. As the solid half 127 of the shaft 125 rotatespast the lip 129 of the lower link 115, the link is released and thelinkage 109 is unconstrained and allowed to collapse to the left asviewed in FIG. 3. The releasing action of the latch 123 occurs onlyinstantaneously. When this occurs, contact arm 97, acting under theforce of spring 107, moves to the contacts-open position and interruptsthe flow of current through the circuit breaker 1' to protect thecontrolled circuit connected to terminals 13 and 15. It should be notedthat since contact arm 97 is retained in the contacts-open position byspring 107, the circuit breaker 1 cannot be reclosed until toggle lever39 is manually moved to the on position. It should further be noted thatcircuit breaker 1 may be provided with alternative circuit paths andterminal arrangements for permitting either current or voltage overloadsensing. For example, the electromagnet coil 69 may be connected in aseparate circuit from the terminals 13, 15 to permit voltage, andcurrent sensing.

As set forth above, the purpose of the present invention is to causedisengagement of the contacts in all'of the poles of a multipole circuitbreaker upon disengagement of the contacts in any one of the poles. Forexample, a circuit operated by a two or three phase power supplyrequires the use of a two or three-pole circuit breaker, respectively,to ensure that each phase of the supply is protected. Should an overloadoccur in one of the phases it is desirous that the power supply to allof the phases be interrupted. Accordingly, the present inventionprovides such a mechanism and FIG. 2 illustrates a two-pole circuitbreaker for use, for example, with a two-phase power supply. It shouldbe understood however that any number of poles may be provided andinterconnected in a row in the manner to be described.

The poles of the two-pole circuit breaker illustrated in FIG. 2 may besecured together by passing the fasteners 27, 35 through both of thehousings 3, 3'. The means for interconnecting the poles for disengagingall of the contacts upon disengagement of either one of the contactscomprises a continuous shaft 133 mounted for rotation in the outer sidewalls of the circuit breaker housings 3, 3. The shaft 133 extendsthrough openings 135, 135 formed in the inner side walls of the housings3, 3' and is provided with a plurality of upwardly projecting cammingmeans or camming lobes 137, 137', one being provided for each pole. Asillustrated in FIGS. 1 and 4, in the contacts-closed position each ofthe camming lobes 137 projects upwardly from the shaft 133 to a positionintermediate a contact arm tab 139 formed on the contact arm 97 and adownwardly projecting finger or tripping member 141 formed on the rotarylatch 123. The contact arm tab 139 is formed adjacent the contact armshaft 105 and is provided with a flange 143 constituting drive means forengaging the camming lobe 137 so as to be operatively connectedtherewith upon rotation of the contact arm 97 about the shaft 105. Aspring 145 is coiled about the shaft 133 and engages the camming lobe137 and the side wall 5' of the housing 3 for biasing the shaft andcamming lobes in a clockwise direction as viewed in FIGS. 1 and 4,flange 143 acting as a stop.

Operation is as follows. The circuit breaker is connectedat terminal 13,15 and 13', 15' to the circuit or component to be protected and thetoggle levers 39, 39 moved to the on or contacts-closed position. Whenan overload occurs in any one of the poles of the circuit breaker, asdetected by the electromagnet 67 therein, the armature 79 in that poleis caused to pivot about the shaft 81 causing the camming surface 95 onthe armature leg 91 to engage and rotate the rotary latch 123 andslotted shaft 125. When the solid half 127 of the slotted shaft 125disengages the lip 129 of the center link 115, the toggle linkageassembly 109 in that pole is tripped and collapses so that the contactarm 97 rotates about the shaft 105 under the urging of spring 107 todisengage the contacts 99 and 19 in that pole. As best illustrated inFIGS. 4 and 5, when the contact arm in the first pole to receive anoverload condition rotates and moves upward to the position shown inFIGS. 3 and 5, the flange 143 formed on the contact arm tab 139 engagesand rotates the lobe 137 associated therewith. Rotation of the lobe 137causes the shaft 133 to rotate, thereby rotating the camming lobe 137into engagement with the downwardly projecting finger 141' formed on therotary latch 123' to rotate the latch 123' and the slotted shaft 125'and permit the remaining toggle assembly 109 to collapse and disengageor trip open the contacts 19, 99. Thus it is seen that an overloadcondition in any one of the poles causes the contact arm in that pole torotate the camming lobe and shaft, whereupon the remaining camming lobesoperate the remaining rotary latches and cause all of the contacts todisengage. To reset the multipole circuit breaker, the toggle levers 39,39' are rotated to the on or contacts-closed position. Since the shaft133 is biased by spring 145 in a clockwise direction, the lobes 137,137' follow flanges 143, 143 on the contact arm tabs 139, 139 back tothe position illustrated in FIG. 4 and permit the rotary latches 123,123' to rotate into engagement therewith.

An important feature of the invention is that the tripping of onecontact brought about by action of its armature part 91 does not effecttripping of any other contact indirectly through action of its armaturebut rather directly by operation of its latch 123 from a lobe 137 onshaft 133.

It will be noted in all of the above embodiments that upon tripping ofone pole all the other poles are tripped. This action takes placeindependently of any restraint on the toggle, providing multipole tripfree action.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantages results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. An interconnected multipole circuit breaker, each pole of whichcomprises supporting means first and second electrical contacts mountedin said supporting means, a movable arm mounted one of said cont-actsfor movement into and out of engagement with the other of said contactsfor controlling an electrical circuit, manually operable means mountedin said housing and movable between first and second positions formoving said movable arm, a linkage assembly connected between saidmanually operable means and said movable arm, said linkage assemblycomprising an extension of said manually operable means, and center andlower pivotally joined links, said lower link having a rotary latchmounted thereon for movement into and out of engagement with said centerlink to effect collapse of said linkage assembly and movement of one ofsaid contacts out of engagement with the other of said contacts, currentresponsive means in said housing having a movable member movable inresponse to a predetermined current flow, said movable member includingportions engageable with said rotary latch to operate the latter andeffect collapse of said linkage assembly, and means for effectingcollapse of the linkage assemblies in all of said poles upon collapse ofthe linkage assembly in any one of said poles, means comprising arotatably mounted shaft passing through all of the poles of said circuitbreaker, said shaft having a plurality of camming members thereon, onefor each pole, said camming members being engageable with the movablearm and rotary latch in each of said poles, whereby collapse of thelinkage assembly in one of said poles causes the movable arm in thatpole to engage and rotate the camming member and shaft associatedtherewith, thereby causing the remaining camming members to rotate theremaining rotary latches and collapse all of the linkage assemblies.

2. A multipole circuit breaker comprising a row of poles, each poleincluding a switch arm spring biased to move to open-circuit position, atoggle mechanism for moving the switch arm to closed-circuit positionagainst the spring bias, tripping means for the toggle to release thearm to move to open-circuit position under the spring bias, anelectro-magnetically operated armature responsive to excess load currentto operate said toggle tripping means,

a continuous rotatable shaft extending across the row of poles, multiplecamming means carried on and simlultaneously operated by said shaft, onecamming means being located in each pole for actuating the toggletripping means therein independently of movement of the armature in therespective pole,

and drive means on each switch arm operatively connected with the one ofthe camming means for operating it and the shaft in response to switchopening movement of the respective arm in one pole thereby to cause eachother camming means to operate a toggle tripping means in each of theother poles.

3. A circuit breaker according to claim 2, wherein each switch arm has alost-motion connection with a fixed pivot for initial rotary movementwhen the switch arm is driven toward closed-circuit position and asecond motion other than around the pivot for actuating on of saidcamming means.

References Cited UNITED STATES PATENTS 3,307,002 2/1967 Cooper 200--1=1'6 3,353,127 1'1/1967 Francis 20O'116 US. Cl. X.R. 200-116

